From 16ba9fbd8041697a0b3f23ec3bb0117216759ec0 Mon Sep 17 00:00:00 2001
From: Matthew Willis <matthew.willis@mac.com>
Date: Mon, 15 Jun 2009 17:09:20 +0900
Subject: [PATCH] extra/central implements the "central" pattern

---
 extra/central/authors.txt          |  1 +
 extra/central/central-docs.factor  | 10 ++++++++++
 extra/central/central-tests.factor |  7 +++++++
 extra/central/central.factor       | 16 ++++++++++++++++
 extra/central/tags.txt             |  1 +
 5 files changed, 35 insertions(+)
 create mode 100644 extra/central/authors.txt
 create mode 100644 extra/central/central-docs.factor
 create mode 100644 extra/central/central-tests.factor
 create mode 100644 extra/central/central.factor
 create mode 100644 extra/central/tags.txt

diff --git a/extra/central/authors.txt b/extra/central/authors.txt
new file mode 100644
index 0000000000..5645cd91bd
--- /dev/null
+++ b/extra/central/authors.txt
@@ -0,0 +1 @@
+Matthew Willis
diff --git a/extra/central/central-docs.factor b/extra/central/central-docs.factor
new file mode 100644
index 0000000000..f6a0ba5957
--- /dev/null
+++ b/extra/central/central-docs.factor
@@ -0,0 +1,10 @@
+USING: central help.markup help.syntax ;
+
+HELP: CENTRAL:
+{ $description
+    "This parsing word defines a pair of words useful for "
+    "implementing the \"central\" pattern: " { $snippet "symbol" } " and "
+    { $snippet "with-symbol" } ".  This is a middle ground between excessive "
+    "stack manipulation and full-out locals, meant to solve the case where "
+    "one object is operated on by several related words."
+} ;
\ No newline at end of file
diff --git a/extra/central/central-tests.factor b/extra/central/central-tests.factor
new file mode 100644
index 0000000000..576a1fac97
--- /dev/null
+++ b/extra/central/central-tests.factor
@@ -0,0 +1,7 @@
+USING: central tools.test ;
+
+IN: scratchpad
+
+CENTRAL: test-central
+
+[ 3 ] [ 3 [ test-central ] with-test-central ] unit-test
\ No newline at end of file
diff --git a/extra/central/central.factor b/extra/central/central.factor
new file mode 100644
index 0000000000..df100f2e5b
--- /dev/null
+++ b/extra/central/central.factor
@@ -0,0 +1,16 @@
+USING: kernel lexer namespaces parser sequences words ;
+
+IN: central
+
+: define-central-getter ( word -- )
+    dup [ get ] curry (( -- obj )) define-declared ;
+
+: define-central-setter ( word with-word -- )
+    [ with-variable ] with (( object quot -- )) define-declared ;
+
+: define-central ( word-name -- )
+    [ create-in dup define-central-getter ] keep
+    "with-" prepend create-in [ define-central-setter ] keep
+    make-inline ;
+
+SYNTAX: CENTRAL: ( -- ) scan define-central ;
\ No newline at end of file
diff --git a/extra/central/tags.txt b/extra/central/tags.txt
new file mode 100644
index 0000000000..f4274299b1
--- /dev/null
+++ b/extra/central/tags.txt
@@ -0,0 +1 @@
+extensions
-- 
2.34.1